[DOCS-509] Explain() works by re-generates the query plan: this can affect timing Created: 10/Sep/12 Updated: 25/Sep/12 Resolved: 10/Sep/12 |
|
| Status: | Closed |
| Project: | Documentation |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | William Zola | Assignee: | Sam Kleinman (Inactive) |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
|
||||
| Participants: | |||||
| Days since reply: | 11 years, 21 weeks, 1 day ago | ||||
| Description |
|
When running a query using the explain() functionality, this will cause the query engine to re-calculate the query plan. This, in turn, can cause some queries to run slower. If you're timing queries, you shouldn't use explain(); if you're explain()ing queries you shouldn't trust the timing. This is not called out in the documentation. |
| Comments |
| Comment by auto [ 25/Sep/12 ] |
|
Author: {u'date': u'2012-09-25T15:48:22-07:00', u'email': u'samk@10gen.com', u'name': u'Sam Kleinman'}Message: |
| Comment by auto [ 25/Sep/12 ] |
|
Author: {u'date': u'2012-09-25T15:48:22-07:00', u'email': u'samk@10gen.com', u'name': u'Sam Kleinman'}Message: |
| Comment by auto [ 10/Sep/12 ] |
|
Author: {u'date': u'2012-09-10T11:12:35-07:00', u'email': u'samk@10gen.com', u'name': u'Sam Kleinman'}Message: |
| Comment by Scott Hernandez (Inactive) [ 10/Sep/12 ] |
|
Yes, explain is not for timing things but only for seeing how they work. |